1到2100年为止_____          2．有更多的空间_________

3．人口的快速增长_____        4．漂浮进入太空___________

5．越来越拥挤_______          6．建立一个更好的世界______

7．以光速的一半_______        8．重力的八分之三__________

9．一条被污染的河______     10．使他们自己变得更重______

11．The heavy traffic is ___________(拥挤的)at this time of a day．

12．The___________ (力量)of gravity makes things fall to earth．

13．What was the___________ (人口)of China in 1900？

14．She took the job for a___________ (特殊的)reason．

15．The Sun is a star，and the Earth is one of its __________ (行星)．

16．At 7 o’clock in the morning, the buses in our city are crowded with___________ (乘客).

17．This new pair of shoes is tight for me, It is _________________(不舒服) to walk.

18．Close your eyes and imagine that there is a _____________(美味的) dish in front of you．

19．He will be chosen to be monitor to do some ____________________(挑战性的) work.

20．Did you have a___________ (令人愉快的)time in the park yesterday?